Let me share some info on how you can add your new accountant to help you manage QuickBooks.
Currently, you'll need to have your previous accountant transfer the master admin rights to your new accountant or delete you from its clients' list to have your new accountant claim the master admin rights. This way, your new accountant will take over and access your QuickBooks account completely.
Here's an article for the detailed instructions that can be done by your previous accountant: Manage clients with wholesale and direct billing. From there, you can guide them to go to Remove clients from wholesale billing section on how to remove you from billing and then let them transfer the admin rights to the new accountant.
Please let me know if you need further assistance. I'll be around to help. Stay safe and well!